Drooping Leaves

hey RIU, it's been a really long time since i've posted. but after a nearly year long hiatus, i'm back in need of some help.

the top leaves on my one plant are drooping and dry to the touch. only the top leaves are affected. i looked into this and cannot figure out what it could be. here's some background info that might help:

-5 gal, DWC w/ drip system
- 1st week of 12/12 lighting, 250w HPS light
- Just used Bushmaster to stop stretch, 3ml per gal of plain water (have used this many times before with no problems)
- Currently running:
-- Advanced Nutrients Grow Micro Bloom, 7.5 ml per gal of each
-- Advanced Nutrients Bud Candy & Big Bud, 5 ml per gal of each
-- Hygrozyme, 10 ml per gal
- pH around 5.5 - 5.9
- Roots from what i can see (plant is pretty big and hard to lift up) are very healthy and white

i've also noticed a little bit of purple in some of the stems, not sure if it is related.

some experienced help would be greatly appreciated. thanks in advance.

i am not familiar with hydro but ive noticed that when my soil plants get droopy its when i havent watered them in a long time or its when i water them too much.
my gut's telling me that thet're not getting enough water
peace

The two most common symptoms i have noticed of droopy leaves are..1) Lack of water make sure your plants have sufficient amounts of water especially when they are the size of yours. They tend to drink lots of water as their root systems develop. If your giving them plenty of water there could be another answer....2) mother nature...this is from the cannabis grow bible ...Toward the end of the light cycle leaves may rest or droop before the dark period begins. If the leaves appear up or reaching for the light during the early to mid light period but look droopy later toward the end of the light period this is natural. Hope that helps.

Yes, it is possible that the leaves are drooping due to lack of water...I also think that it may have something to do with the roots...what nutrients are you feeding them? It could be receiving too much "unwanted" nutrients that's why the leaves are drooping...

Droopy can be from air flow lacking also.If buckets are full I would stir up more air in there

thanks for all the responses and suggestions. to answer all of your questions...

almost certain it's not an issue of overwatering, underwatering, or drowning. running dwc so there is a lot of water and my bucket has a lot of bubbles so i'm not drowning them. but i will get another airstone this weekend and throw it in, just to be safe. can never have too much bubbles. plus using the 5 gallon netpot so a lot of the roots are above water getting plenty of air.

as for nutrients, actually mentioned it in my first post... advanced nutrients. for more details, it's all in my first post. as of now, this is at the top of the list for the cause.

i'm hoping it's something along the lines of what headshots420 said about it just being mother nature. none of my plants have ever done this before so it's a first if this is the cause.

i'll keep everyone posted with progress and if i need more help.

could be humidity or temps also.
are you using beneficials or do you flush your roots and buckets? could be the start of some sort of fungus/bacteria covering the roots making water up-keep hard.

What is your ppm before, and after you add nutes?
Purple stems are probably coused by genetics or Phosphorus deficiency(low temp. when lights are off?). If your roots look fine, it may be beginning of the problem with gnats, i would put few yellow sticky traps around the base and see if gnats are present. I do not see any burnt tips on that pic. but there is a chance that she has been slightly over fertilized. If your temp. is around 65-70'F, rel. humidity around 50-55 '/. and you have fans moving air around, i would say it is simply too much water,..with or without nutes.
Those leaves look thick and over saturated, slightly wrinkled, but no burn signs or discoloration, she looks thick and healthy besides droopines. Sadly I do not have any exp. with DWC, but I would try to decrease the volume of the water that is inside the bucket, and put a high quality air-stone, biggest one that i can fit in that bucket. Good luck my friend.